During the American Civil War, Lieutenant Colonel William McCullough, fighting for the Union, died heroically trying to rally his troops during an ambush. He was one of thousands who perished in that deadliest of American wars, but President Abraham Lincoln had a personal connection to this soldier. He had become acquainted with the McCullough family during his days as an attorney in Illinois, and the two men had served together during the Black Hawk War.

So when Lincoln heard of Colonel McCullough’s death, he felt moved to write a personal letter of consolation to his friend’s 22-year-old daughter, Fanny. It was a tense, critical time for the president—the Union had just suffered a crippling defeat at Fredericksburg, and the question about whether or not to emancipate the slaves weighed heavily on Lincoln’s mind. But he knew he had to reach out to Fanny, who, according to her family, had shut herself up in her room, refusing to eat, “pacing the floor in violent grief.”1

Lincoln knew much about grief himself. His mother, Nancy, had died when he was only a child. And Lincoln and his wife were still mourning the loss of their 11-year-old son Willie, who had passed away just a few months earlier. So it was from personal, still-tender experience that Lincoln wrote: “In this sad world of ours, sorrow comes to all; and, to the young, it comes with bitterest agony, because it takes them unawares. The older have learned to ever expect it.”

But Lincoln’s counsel was not simply to expect sorrow; rather, it was to expect happiness. “You are sure to be happy again,” he promised. “The memory of your dear Father, instead of an agony, will yet be a sad sweet feeling in your heart, of a purer, and holier sort than you have known before.”2

Over his career, Abraham Lincoln penned many official communications and almost as many condolence letters. But this one stands out as especially gentle and compassionate—perhaps because it seems to come, as the signature line says, from a “sincere friend,” from one griever to another, from one who had “experience enough to know” what it feels like to grieve.3 And all of this makes its main message—to Fanny and to all of us—so much more powerful: whatever your heartbreak, you are sure to be happy again.